Method and apparatus for sensing an environmental condition during frequency hopping

ABSTRACT

A method includes receiving a series of radio frequency (RF) signals, where, from RF signal to RF signal of the series of RF signals, a carrier frequency is changed in accordance with a frequency hopping pattern. The method further includes, while receiving the series of RF signals, sensing an environmental condition by, for a frequency hop of at least some frequency hops of the frequency hopping pattern, adjusting a characteristic of a wireless sensor to maintain proximal alignment of a resonant frequency of the wireless sensor with the carrier frequency corresponding to a present frequency of the at least some frequency hops and generating a value to represent the adjustment of the characteristic, where a set of values is generated for the at least some frequency hops and where the set of values is used to determine a sensed value of the environmental condition.

CROSS REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. § 120 as a continuation-in-part of U.S. Utility applicationSer. No. 14/727,523, entitled “Method and Apparatus for SensingEnvironmental Parameters Using Wireless Sensor(s),” filed Jun. 1, 2015,now U.S. Pat. No. 9,991,596, issued on Jun. 5, 2018, which claimspriority pursuant to 35 U.S.C. § I 19(e) to U.S. Provisional 10Application No. 62/004,941, entitled “Pressure/Proximity SensorsReference Design,” filed May 30, 2014; U.S. Provisional Application No.62/004,943, entitled “Method and Apparatus for Varying an Impedance,”filed May 30, 2014; U.S. Provisional Application No. 62/011,116,entitled “Method and Apparatus for Sensing Water Level Using WirelessSensor(s),” filed Jun. 12, 2014; and U.S. Provisional Application No.62/131,414, entitled 15 “Method and Apparatus for Variable CapacitorControl,” filed Mar. 11, 2015, all of which are hereby incorporatedherein by reference in their entirety and made part of the present U.S.Utility Patent Application for all purposes.

U.S. Utility patent application Ser. No. 14/727,523 also claims prioritypursuant to 35 U.S.C § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 14/256,877, entitled 20 “METHOD AND APPARATUS FORSENSING ENVIRONMENT USING A WIRELESS PASSIVE SENSOR”, filed Apr. 18,2014, now U.S. Pat. No. 9,785,807, issued on Oct. 10, 2017, which claimspriority pursuant to 35 U.S.C. § I 19(e) to U.S. Provisional ApplicationNo. 61/814,241, entitled “RFID ENVIRONMENTAL SENSOR”, filed Apr. 20,2013; U.S. Provisional Application No. 61/833,150, entitled “RESONANTANTENNA”, filed Jun. 10, 2013; U.S. Provisional 25 Application No.61/833,167, entitled “RFID TAG”, filed Jun. 10, 2013; U.S. ProvisionalApplication No. 61/833,265, entitled “RFID TAG”, filed Jun. 10, 2013;U.S. Provisional Application No. 61/871,167, entitled “RESONANTANTENNA”, filed Aug. 28, 2013; U.S. Provisional Application No.61/875,599, entitled “CMF ACCURATE SENSOR”, filed Sep. 9, 2013; U.S.Provisional Application No. 61/896,102, entitled “RESONANT 30 ANTENNA”,filed Oct. 27, 2013; U.S. Provisional Application No. 61/929,017,entitled “RFID ENVIRONMENTAL SENSOR”, filed Jan. 18, 2014; U.S.Provisional Application No. 61/934,935, entitled “RFID ENVIRONMENTALSENSOR”, filed Feb. 3, 2014; all of which are hereby incorporated hereinby reference in their entirety and made part of the present U.S. UtilityPatent Application for all purposes.

U.S. Utility application Ser. No. 14/256,877 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 13/209,420, entitled “METHOD AND APPARATUS FORDETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, now U.S. Pat. No.8,749,319, issued on Jun. 10, 2014, which claims priority pursuant to 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/428,170, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Dec. 29, 2010 andU.S. Provisional Application No. 61/485,732, entitled “METHOD ANDAPPARATUS FOR SENSING ENVIRONMENTAL CONDITIONS USING AN RFID TAG”, filedMay 13, 2011, all of which are hereby incorporated herein by referencein their entirety and made part of the present U.S. Utility PatentApplication for all purposes. U.S. Utility application Ser. No.13/209,420 also claims priority pursuant to 35 U.S.C. § 120 as acontinuation-in-part of U.S. Utility application Ser. No. 12/462,331,entitled “METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Aug. 1,2009, now U.S. Pat. No. 8,081,043, issued on Dec. 20, 2011, which is adivisional of U.S. Utility application Ser. No. 11/601,085, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Nov. 18, 2006,now U.S. Pat. No. 7,586,385, issued on Sep. 8, 2009, all of which arehereby incorporated herein by reference in their entirety and made partof the present U.S. Utility Patent Application for all purposes.

U.S. Utility application Ser. No. 14/256,877 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 13/209,425, entitled “METHOD AND APPARATUS FORDETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, now U.S. Pat. No.9,048,819, issued on Jun. 2, 2015, which claims priority pursuant to 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/428,170, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Dec. 29, 2010 andU.S. Provisional Application No. 61/485,732, entitled “METHOD ANDAPPARATUS FOR SENSING ENVIRONMENTAL CONDITIONS USING AN RFID TAG”, filedMay 13, 2011, all of which are hereby incorporated herein by referencein their entirety and made part of the present U.S. Utility PatentApplication for all purposes.

U.S. Utility application Ser. No. 13/209,425 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 12/462,331, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Aug. 1, 2009, now U.S. Pat. No. 8,081,043,issued on Dec. 20, 2011, which is a divisional of U.S. Utilityapplication Ser. No. 11/601,085, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Nov. 18, 2006, now U.S. Pat. No. 7,586,385,issued on Sep. 8, 2009, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. UtilityPatent Application for all purposes.

U.S. Utility application Ser. No. 14/256,877 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 13/467,925, entitled “ROLL-TO-ROLL PRODUCTION OFRFID TAGS”, filed May 9, 2012, which is a continuation-in-part of U.S.Utility application Ser. No. 13/209,425, entitled “METHOD AND APPARATUSFOR DETECTING RF FIELD STRENGTH”, filed Aug. 14, 2011, now U.S. Pat. No.9,048,819, issued on Jun. 2, 2015, which claims priority pursuant to 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/428,170, entitled“METHOD AND APPARATUS FOR VARYING AN IMPEDANCE”, filed Dec. 29, 2010 andU.S. Provisional Application No. 61/485,732, entitled “METHOD ANDAPPARATUS FOR SENSING ENVIRONMENTAL CONDITIONS USING AN RFID TAG”, filedMay 13, 2011, all of which are hereby incorporated herein by referencein their entirety and made part of the present U.S. Utility PatentApplication for all purposes.

U.S. Utility application Ser. No. 13/209,425 also claims prioritypursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S. Utilityapplication Ser. No. 12/462,331, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Aug. 1, 2009, now U.S. Pat. No. 8,081,043,issued on Dec. 20, 2011, which is a divisional of U.S. Utilityapplication Ser. No. 11/601,085, entitled “METHOD AND APPARATUS FORVARYING AN IMPEDANCE”, filed Nov. 18, 2006, now U.S. Pat. No. 7,586,385,issued on Sep. 8, 2009, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. UtilityPatent Application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION Technical Field of the Invention

This application relates generally to wireless data communicationsystems and more particularly to processing data representative ofenvironmental sensed conditions.

DESCRIPTION OF RELATED ART

Wireless communication systems are known to include wirelesstransceivers that communication directly and/or over a wirelesscommunication infrastructure. In direct wireless communications, a firstwireless transceiver includes baseband processing circuitry and atransmitter to convert data into a wireless signal (e.g., radiofrequency (RF), infrared (IR), ultrasound, near field communication(NFC), etc.). Via the transmitter, the first wireless transceivertransmits the wireless signal. When a second wireless transceiver is inrange (e.g., is close enough to the first wireless transceiver toreceive the wireless signal at a sufficient power level), it receivesthe wireless signal via a receiver and converts the signal intomeaningful information (e.g., voice, data, video, audio, text, etc.) viabaseband processing circuitry. The second wireless transceiver maywirelessly communicate back to the first wireless transceiver in asimilar manner.

Examples of direct wireless communication (or point-to-pointcommunication) include walkie-talkies, Bluetooth, ZigBee, RadioFrequency Identification (RFID), etc. As a more specific example, whenthe direct wireless communication is in accordance with RFID, the firstwireless transceiver may be an RFID reader and the second wirelesstransceiver may be an RFID tag.

For wireless communication via a wireless communication infrastructure,a first wireless communication device transmits a wireless signal to abase station or access point, which conveys the signal to a wide areanetwork (WAN) and/or to a local area network (LAN). The signal traversesthe WAN and/or LAN to a second base station or access point that isconnected to a second wireless communication device. The second basestation or access point sends the signal to the second wirelesscommunication device. Examples of wireless communication via aninfrastructure include cellular telephone, IEEE 802.11, public safetysystems, etc.

In many situations, direct wireless communication is used to gatherinformation that is then communicated to a computer. For example, anRFID reader gathers information from RFID tags via direct wirelesscommunication. At some later point in time (or substantiallyconcurrently), the RFID reader downloads the gathered information to acomputer via a direct wireless communication or via a wirelesscommunication infrastructure.

In many RFID systems, the RFID tag is a passive component. As such, theRFID tag has to generate one or more supply voltages from the RF signalstransmitted by the RFID reader. Accordingly, a passive RFID tag includesa power supply circuit that converts the RF signal (e.g., a continuouswave AC signal) into a DC power supply voltage. The power supply circuitincludes one or more diodes and one or more capacitors. The diode(s)function to rectify the AC signal and the capacitor(s) filter therectified signal to produce the DC power supply voltage, which powersthe circuitry of the RFID tag.

Once powered, the RFID tag receives a command from the RFID reader toperform a specific function. For example, if the RFID tag is attached toa particular item, the RFID tag stores a serial number, or some otheridentifier, for the item. In response to the command, the RFID tagretrieves the stored serial number and, using back-scattering, the RFIDtag transmits the retrieved serial number to the RFID reader.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice in accordance with the present invention;

FIG. 3 is a schematic block diagram of an example of a sensor computingdevice communicating with a passive wireless sensor in accordance withthe present invention;

FIG. 4 is a schematic block diagram of another example of a sensorcomputing device communicating with a passive wireless sensor inaccordance with the present invention;

FIG. 5 is a schematic block diagram of an example of a plurality ofcomponents of a radio frequency (RF) receiving circuit in accordancewith the present invention;

FIG. 6 is a schematic block diagram of another example of a plurality ofcomponents of a radio frequency (RF) receiving circuit in accordancewith the present invention; and

FIG. 7 is a logic diagram of an example of sensing an environmentalcondition during frequency hopping in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem 10 that includes a plurality of sensor computing devices 12, aplurality of user computing devices 14, a plurality of passive wirelesssensors 16-1 through 16-4, one or more wide area networks (WAN), and oneor more local area networks (LAN). The passive wireless sensors 16-1through 16-4, when activated, sense one or more of a variety ofconditions. For example, one passive wireless sensor senses for thepresence, absence, and/or amount of moisture in a given location (e.g.,in a room, in a manufactured item or component thereof (e.g., avehicle), in a bed, in a diaper, etc.). As another example, a passivewireless sensor senses pressure on and/or in a particular item (e.g., ona seat, on a bed, in a tire, etc.).

As yet another example, a passive wireless sensor senses temperaturewithin a space and/or of an item (e.g., surface temperature of the item,in a confined space such as a room or a box, etc.). As a furtherexample, a passive wireless sensor senses humidity within a space (e.g.,a room, a closet, a box, a container, etc.). As a still further example,a passive wireless sensor senses the presence and/or percentages of agas within a space (e.g., carbon monoxide in a car, carbon monoxide in aroom, gas within a food container, etc.). As an even further example, apassive wireless sensor senses the presence and/or percentages of alight within a space. As yet a further example, a passive wirelesssensor senses the presence, percentages, and/or properties of one ormore liquids in a solution. In one more example, a passive wirelesssensor senses location proximity of one item to another and/or theproximity of the passive wireless sensor to an item (e.g., proximity toa metal object, etc.).

In general, the sensor computing devices 12 function to collect thesensed data from the passive wireless sensors and process the senseddata. For example, a passive wireless sensor generates a coded valuerepresentative of a sensed condition (e.g., amount of moisture). Asensor computing device 12 receives the coded value and processes it todetermine an accurate measure of the sensed condition (e.g., a valuecorresponding to the amount of moisture such as 0% saturated, 50%saturated, 100% saturated, etc.).

The user computing devices 14 communicate with one or more of the sensorcomputing devices 12 to gather the accurate measures of sensedconditions for further processing. For example, assume that the wirelesscommunication system is used by a manufacturing company that hasmultiple locations for assembly of its products. In particular, LAN 1 isat a first location where a first set of components of products areprocessed and the LAN 2 is at a second location where second componentsof the products and final assembly of the products occur. Further assumethat the corporate headquarters of the company is at a third location,where it communicates with the first and second locations via the WANand LANs.

In this example, the sensor computing device 12 coupled to LAN 1collects and processes data regarding the first set of components assensed by passive wireless sensors 16-1 and 16-2. The sensor computingdevice 12 is able to communicate this data to the user computing device14 coupled to the LAN 1 and/or to the computing device 14 at corporateheadquarters via the WAN. Similarly, the sensor computing device 12coupled to LAN 2 collects and processes data regarding the second set ofcomponents and final assembly as sensed by passive wireless sensors 16-3and 16-4. This sensor computing device 12 is able to communicate thisdata to the user computing device 14 coupled to the LAN 2 and/or to thecomputing device 14 at corporate headquarters via the WAN. In such asystem, real time monitoring is available locally (e.g., via the LAN)and is further available non-locally (e.g., via the WAN). Note that anyof the user computing devices 14 may receive data from the any of thesensor computing devices 12 via a combination of LANs and the WAN.

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice 12 and/or 14 that includes a computing core 20, one or more inputdevices 48 (e.g., keypad, keyboard, touchscreen, voice to text, etc.),one or more audio output devices 50 (e.g., speaker(s), headphone jack,etc.), one or more visual output devices 46 (e.g., video graphicsdisplay, touchscreen, etc.), one or more universal serial bus (USB)devices, one or more networking devices (e.g., a wireless local areanetwork (WLAN) device 54, a wired LAN device 56, a wireless wide areanetwork (WWAN) device 58 (e.g., a cellular telephone transceiver, awireless data network transceiver, etc.), and/or a wired WAN device 60),one or more memory devices (e.g., a flash memory device 62, one or morehard drives 64, one or more solid state (SS) memory devices 66, and/orcloud memory 96), one or more peripheral devices, and/or a transceiver70.

The computing core 20 includes a video graphics processing unit 28, oneor more processing modules 22, a memory controller 24, main memory 26(e.g., RAM), one or more input/output (I/O) device interface module 36,an input/output (I/O) interface 32, an input/output (I/O) controller 30,a peripheral interface 34, one or more USB interface modules 38, one ormore network interface modules 40, one or more memory interface modules42, and/or one or more peripheral device interface modules 44. Each ofthe interface modules 36-44 includes a combination of hardware (e.g.,connectors, wiring, etc.) and operational instructions stored on memory(e.g., driver software) that is executed by the processing module 22and/or a processing circuit within the respective interface module. Eachof the interface modules couples to one or more components of thecomputing device 12-14. For example, one of the IO device interfacemodules 36 couples to an audio output device 50. As another example, oneof the memory interface modules 42 couples to flash memory 62 andanother one of the memory interface modules 42 couples to cloud memory68 (e.g., an on-line storage system and/or on-line backup system).

The transceiver 70 is coupled to the computing core 20 via a USBinterface module 38, a network interface module 40, a peripheral deviceinterface module 44, or a dedicated interface module (not shown).Regardless of how the transceiver 70 is coupled to the computing core,it functions to communicate with the passive wireless sensors.

FIG. 3 is a schematic block diagram of an example of a sensor computingdevice 12 communicating with a passive wireless sensor 16 (e.g., any oneof 16-1 through 16-4). The sensor computing device 12 is illustrated ina simplified manner; as such, it shown to include the transceiver 70, anantenna 96, the processing module 22, and the memory (e.g., one or moreof 26 and 62-68). The passive wireless sensor 16 includes a radiofrequency (RF) receiving circuit 75, one or more sensing elements 58, aprocessing module 84, a memory 88, and an RF transmitting circuit 85.The RF receiving circuit 75 is operable to receive a series of radiofrequency (RF) signals where each RF signal has a carrier frequency of aplurality of carrier frequencies 67. From RF signal to RF signal of theseries of RF signals received, the carrier frequency is changed inaccordance with a frequency hopping pattern 73. As shown, frequencyhopping 73 occurs among channels 89 within a frequency band 87. Forexample, the frequency band 87 includes frequencies in the range of 902MHz to 928 MHz and includes 50 channels (e.g., 50 different carrierfrequencies). The frequency hopping 73 among the channels 89 may be inaccordance with a standard (e.g., RFID standard), in accordance with apredetermined pattern, in accordance with a periodic pattern, inaccordance with a non-sequential pattern, or in accordance with a random(e.g., completely random or pseudo-random) pattern. The time betweeneach frequency hop may be standardized, predetermined, or random (e.g.,completely random or pseudo-random).

The wireless sensor 16 includes a plurality of components and thecharacteristics (e.g., impedance) of those components establish aresonant frequency of the wireless sensor. In an example, the sensingelement 58 of the passive wireless sensor 16 senses an environmentalcondition 65 of an object. The environmental condition includes, but isnot limited to, one or more of moisture, temperature, pressure,humidity, altitude, sonic wave (e.g., sound), human contact, surfaceconditions, tracking, location (e.g., proximity), etc. The objectincludes one or more of, but is not limited to, a box, a personal item(e.g., clothes, diapers, etc.), a pet, an automobile component, anarticle of manufacture, an item in transit, etc. The sensing element 58senses the environmental condition (e.g., moisture) and, as a result ofthe sensed condition, the sensing element 58 affects an operationalparameter (e.g., input impedance, quality factor, frequency, etc.) ofthe plurality of components of the wireless sensor. As a specificexample, the sensing element 58, as a result of the sensed environmentalcondition 65, causes an impedance effect 63 on the RF receiving circuit75 that affects the resonant frequency of the RF receiving circuit 75.

As the RF receiving circuit receives the series of RF signals in thefrequency hopping pattern 73, the processing module 84 adjusts thewireless sensor characteristics in order to sense the environmentalcondition 65. More specifically, for a frequency hop of at least somefrequency hops of the frequency hopping pattern 73 received, theprocessing module 84 adjusts a characteristic of the wireless sensor tomaintain proximal alignment of the resonant frequency of the wirelesssensor with the carrier frequency corresponding to a present frequencyof the at least some frequency hops. The processing module 84 can thengenerate a value to represent the adjustment of the characteristic.Thus, a set of values 77 is generated for the at least some frequencyhops and is used to determine a sensed value of the environmentalcondition 65. For example, the set of values 77 is normalized by thewireless sensor 16 (e.g., by the processing module) or by the sensorcomputing device 12 to produce a normalized value 79 that represents thesensed value of the environmental condition 65. For example, the RFtransmitting circuit 85 is operable to transmit the set of values 77 orthe normalized value 79 to the sensor computing device 12. When the RFtransmitting circuit 85 transmits the set of values 77 to the sensorcomputing device 12, the sensor computing device 12 is operable tonormalize the set of values 77 to produce the normalized value 79.Alternatively, the wireless sensor normalizes the set of values 77 andtransmits the normalized value 79 to the sensor computing device 12.

The set of values 77 is normalized (e.g., by the wireless sensor or thesensor computing device) to produce the normalized value 79 byidentifying a subset of the values of the set of values corresponding toa subset of carrier frequencies of a plurality of frequencies of theseries of RF signals. The subset of values is then normalized based onfrequency differences between the subset of carrier frequencies anddifferences between values of the subset of values.

FIG. 4 is a schematic block diagram of an embodiment of another exampleof the sensor computing device 12 communicating with the passivewireless sensor 16 (e.g., any one of 16-1 through 16-4). The passivewireless sensor 16 includes a radio frequency (RF) receiving circuit 75,one or more sensing elements 58, a processing module 84, and a memory88. The RF receiving circuit includes a plurality of components whichmay include an antenna 80, a power harvesting circuit 82, a powerdetection circuit 86, a tuning circuit 90, a receiver section 92, and/ora transmitter section 94 (e.g., the RF transmitting circuit).

In an example, the sensing element 58 of the passive wireless sensor 16senses an environmental condition of an object. The environmentalcondition includes, but is not limited to, one or more of moisture,temperature, pressure, humidity, altitude, sonic wave (e.g., sound),human contact, surface conditions, tracking, location, etc. The objectincludes one or more of, but is not limited to, a box, a personal item(e.g., clothes, diapers, etc.), a pet, an automobile component, anarticle of manufacture, an item in transit, etc. The sensing element 58senses the environmental condition (e.g., moisture) and, as a result ofthe sensed condition, the sensing element 58 affects an operationalparameter (e.g., input impedance, quality factor, frequency, etc.) of anRF front end of the passive wireless sensor. Note that the RF front endincludes one or more of the antenna 80, the tuning circuit 90, thetransmitter section 94, the receiver section 92.

As a specific example, the sensing element 58, as a result of the sensedenvironmental condition 65, causes an impedance effect on the RFreceiving circuit 75, an effect on the input impedance of the antennastructure 80 and/or of the tuning circuit 90 (e.g., a tank circuit thatincludes one or more capacitors and one or more inductors having aresonant frequency corresponding to the carrier frequency of the RFsignal). However, as the environmental condition 65 cause an impedanceeffect, the RF receiving circuit is also receiving RF signals in afrequency hopping pattern. In order to determine the sensedenvironmental condition as the carrier frequency changes, the processingmodule 84 adjusts a characteristic of the wireless sensor to maintainproximal alignment of the resonant frequency of the wireless sensor withthe carrier frequency corresponding to a present frequency of the atleast some frequency hops. The processing module 84 generates, for eachfrequency hop, a value to represent the adjustment of the characteristicand creates a set of values for the at least some frequency hops. Theset of values is used to determine a sensed value of the environmentalcondition. For instance, the set of values is normalized to produce anormalized value that represents a sensed value of the environmentalcondition. The RF transmitting circuit 85 is operable to transmit theset of values 77 or the normalized value 79 to the sensor computingdevice 12.

In addition to processing the sensed environmental condition, theprocessing module 84 processes a power level adjustment. For example,the power detection circuit 86 detects a power level of the received RFsignal. In one embodiment, the processing module interprets the powerlevel and communicates with the sensor computing device 12 to adjust thepower level of the RF signal transmitted by the computing device 12 to adesired level (e.g., optimal for accuracy in detecting the environmentalcondition). In another embodiment, the processing module 84 includes thereceived power level data with the environmental sensed data it sends tothe sensor computing device 12 so that the computing device can factorthe power level into the determination of the environmental condition.

FIG. 5 is a schematic block diagram of an example of a plurality ofcomponents of a radio frequency (RF) receiving circuit of the wirelesssensor 16. As shown, the plurality of components of the RF receivingcircuit includes an antenna operable to receive a series of RF signals,and a tuning circuit 90. The inductance of antenna 80 is coupled to acapacitor 93 (e.g., one or more of a varactor and a selectable capacitorbank) to form a tank circuit 97. The tuning circuit 90 includes anadjusting circuit 91. As the RF receiving circuit is receiving theseries of RF signals in the frequency hopping pattern, the processingmodule may instruct the adjusting circuit 91 to adjust the capacitanceof the capacitor 93 (i.e., the tank circuit capacitance is thecharacteristic of the wireless sensor to be adjusted) to align theresonant frequency of the wireless sensor with the carrier frequencycorresponding to a present frequency of the at least some frequencyhops.

FIG. 6 is a schematic block diagram of another example of a plurality ofcomponents of a radio frequency (RF) receiving circuit. The plurality ofcomponents of the RF receiving circuit includes an antenna 80 operableto receive a series of RF signals, and a tuning circuit. The tuningcircuit 90 includes an adjusting circuit 91, a capacitor 93 (e.g., oneor more of a varactor and a selectable capacitor bank), and an inductor95. The capacitor 93 and the inductor 95 are coupled to form a tankcircuit 97 that is operably coupled to the antenna 80.

As the RF receiving circuit is receiving the series of RF signals in thefrequency hopping pattern, the processing module may instruct theadjusting circuit 91 to adjust the capacitance of the capacitor 93(i.e., the tank circuit capacitance is the characteristic of thewireless sensor to be adjusted) to align the resonant frequency of thewireless sensor with the carrier frequency corresponding to a presentfrequency of the at least some frequency hops. Alternatively, as the RFreceiving circuit is receiving the series of RF signals in the frequencyhopping pattern, the processing module may instruct the adjustingcircuit 91 to adjust the impedance of the antenna 80 (i.e., the antennaimpedance is the characteristic of the wireless sensor to be adjusted)to align the resonant frequency of the wireless sensor with the carrierfrequency corresponding to a present frequency of the at least somefrequency hops. Alternatively, as the RF receiving circuit is receivingthe series of RF signals in the frequency hopping pattern, theprocessing module may instruct the adjusting circuit 91 to adjust theinductance of the inductor 95 (i.e., the inductance of the tank circuitis the characteristic of the wireless sensor to be adjusted) to alignthe resonant frequency of the wireless sensor with the carrier frequencycorresponding to a present frequency of the at least some frequencyhops.

FIG. 7 is a logic diagram of an example of sensing an environmentalcondition during frequency hopping. The method begins at step 98 where awireless sensor (e.g., the RF receiving circuit 75 of the passivewireless sensor 16) receives a series of radio frequency (RF) signalswhere from RF signal to RF signal of the series of RF signals received,the carrier frequency is changed in accordance with a frequency hoppingpattern. Frequency hopping occurs among channels within a frequencyband. For example, the frequency band includes frequencies in the rangeof 902 MHz to 928 MHz and may include 50 channels (e.g., 50 differentcarrier frequencies). The frequency hopping among the channels may be inaccordance with a standard (e.g., RFID standard), in accordance with apredetermined pattern, in accordance with a periodic pattern, inaccordance with a non-sequential pattern, or in accordance with a random(e.g., completely random or pseudo-random) pattern. The time betweeneach frequency hop may be standardized, predetermined, or random (e.g.,completely random or pseudo-random). When the wireless sensor is exposedto an environmental condition, the resonant frequency of the wirelesssensor is affected. The environmental condition includes, but is notlimited to, one or more of moisture, temperature, pressure, humidity,altitude, sonic wave (e.g., sound), human contact, surface conditions,tracking, location, proximity, etc.

In order to sense the environmental condition as the wireless sensor isreceiving the series of RF signals in the frequency hopping pattern, themethod continues at step 100 where, for a frequency hop of at least somefrequency hops of the frequency hopping pattern received, acharacteristic of the wireless sensor is adjusted to maintain proximalalignment of the resonant frequency of the wireless sensor with thecarrier frequency corresponding to a present frequency of the at leastsome frequency hops. The adjusting of the characteristic may includeadjusting capacitance of the wireless sensor's tank circuit where thetank circuit is coupled to an antenna that receives the series of RFsignals. The adjusting of the characteristic may alternatively includeadjusting impedance of an antenna of the wireless sensor to affect theresonant frequency, adjusting capacitance of a capacitor (e.g., one ormore of a varactor and a selectable capacitor bank) of the wirelesssensor to affect the resonant frequency, and/or adjusting inductance ofan inductor of the wireless sensor to affect the resonant frequency.

The method continues at step 102 where the wireless sensor generates avalue to represent each adjustment of the characteristic. Thus, a set ofvalues is generated for the at least some frequency hops as the seriesof RF signals are received in the frequency hopping pattern and the setof values is used to determine a sensed value of the environmentalcondition.

For example, the set of values is normalized to produce a normalizedvalue that represents a sensed value of the environmental condition. Theset of values can be normalized by the wireless sensor or by the sensorcomputing device. For example, the wireless sensor may send the set ofvalues to the sensor computing device and the sensor computing devicenormalizes the set of values to produce the normalized value.Alternatively, the wireless sensor normalizes the set of values toproduce the normalized value and is able to transmit the normalizedvalue to the sensor computing device. The set of values is normalized(e.g., by the wireless sensor or the sensor computing device) to producethe normalized value by identifying a subset of the values of the set ofvalues corresponding to a subset of carrier frequencies of a pluralityof frequencies of the series of RF signals. The subset of values is thennormalized based on frequency differences between the subset of carrierfrequencies and differences between values of the subset of values.

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, audio, etc. any of which may generally be referred to as‘data’). As may be used herein, the terms “substantially” and“approximately” provides an industry-accepted tolerance for itscorresponding term and/or relativity between items. Such anindustry-accepted tolerance ranges from less than one percent to fiftypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. Such relativity between items rangesfrom a difference of a few percent to magnitude differences. As may alsobe used herein, the term(s) “configured to”, “operably coupled to”,“coupled to”, and/or “coupling” includes direct coupling between itemsand/or indirect coupling between items via an intervening item (e.g., anitem includes, but is not limited to, a component, an element, acircuit, and/or a module) where, for an example of indirect coupling,the intervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “configured to”, “operable to”,“coupled to”, or “operably coupled to” indicates that an item includesone or more of power connections, input(s), output(s), etc., to perform,when activated, one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, and/or “processing unit” may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may be, or furtherinclude, memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of another processing module, module, processing circuit,and/or processing unit. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.

Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with other routines. In this context, “start” indicates thebeginning of the first step presented and may be preceded by otheractivities not specifically shown. Further, the “continue” indicationreflects that the steps presented may be performed multiple times and/ormay be succeeded by other activities not specifically shown. Further,while a flow diagram indicates a particular ordering of steps, otherorderings are likewise possible provided that the principles ofcausality are maintained.

The one or more embodiments are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical embodiment of an apparatus, an article ofmanufacture, a machine, and/or of a process may include one or more ofthe aspects, features, concepts, examples, etc. described with referenceto one or more of the embodiments discussed herein. Further, from figureto figure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

While the transistors in the above described figure(s) is/are shown asfield effect transistors (FETs), as one of ordinary skill in the artwill appreciate, the transistors may be implemented using any type oftransistor structure including, but not limited to, bipolar, metal oxidesemiconductor field effect transistors (MOSFET), N-well transistors,P-well transistors, enhancement mode, depletion mode, and zero voltagethreshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theembodiments. A module implements one or more functions via a device suchas a processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

While particular combinations of various functions and features of theone or more embodiments have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A method for execution by a wireless sensor, themethod comprises: receiving a series of radio frequency (RF) signals,wherein, from RF signal to RF signal of the series of RF signals, acarrier frequency is changed in accordance with a frequency hoppingpattern; and while receiving the series of RF signals, sensing anenvironmental condition by: for a frequency hop of at least somefrequency hops of the frequency hopping pattern: adjusting acharacteristic of the wireless sensor to maintain proximal alignment ofa resonant frequency of the wireless sensor with the carrier frequencycorresponding to a present frequency of the at least some frequencyhops; and generating a value to represent the adjustment of thecharacteristic, wherein a set of values is generated for the at leastsome frequency hops, wherein the set of values is used to determine asensed value of the environmental condition.
 2. The method of claim 1,wherein the frequency hopping pattern comprises: a periodic, anon-sequential, or a random pattern to switch the carrier frequency of aplurality of carrier frequencies to another carrier frequency of theplurality of carrier frequencies.
 3. The method of claim 1, wherein theadjusting the characteristic comprises: adjusting capacitance of a tankcircuit coupled to an antenna that receives the series of RF signals,wherein the wireless sensor includes the tank circuit and the antenna.4. The method of claim 1, wherein the adjusting the characteristiccomprises one of: adjusting impedance of an antenna of the wirelesssensor to affect the resonant frequency; adjusting capacitance of acapacitor of the wireless sensor to affect the resonant frequency,wherein the capacitor includes one or more of a varactor and aselectable capacitor bank; and adjusting inductance of an inductor ofthe wireless sensor to affect the resonant frequency.
 5. The method ofclaim 1 further comprises: sending, by the wireless sensor, the set ofvalues for the at least some frequency hops to a sensor computingdevice, wherein the sensor computing device normalizes the set of valuesto produce a normalized value that represents the sensed value of theenvironmental condition; or normalizing, by the wireless sensor, the setof values to produce the normalized value and sending, by the wirelesssensor, the normalized value to the sensor computing device.
 6. Themethod of claim 5, wherein the normalizing the set of values comprises:identifying a subset of the values of the set of values corresponding toa subset of carrier frequencies of a plurality of frequencies of theseries of RF signals; and normalizing the subset of values based onfrequency differences between the subset of carrier frequencies anddifferences between values of the subset of values.
 7. A wireless sensorcomprises: a radio frequency (RF) receiving circuit operable to receivea series of radio frequency (RF) signals, wherein, from RF signal to RFsignal of the series of RF signals, a carrier frequency is changed inaccordance with a frequency hopping pattern; and a processing moduleoperably coupled to the RF receiving circuit, wherein the processingmodule is operable to sense an environmental condition by: for afrequency hop of at least some frequency hops of the frequency hoppingpattern: adjusting a characteristic of the wireless sensor to maintainproximal alignment of a resonant frequency of the wireless sensor withthe carrier frequency corresponding to a present frequency of the atleast some frequency hops; and generating a value to represent theadjustment of the characteristic, wherein a set of values is generatedfor the at least some frequency hops, wherein the set of values is usedto determine a sensed value of the environmental condition.
 8. Thewireless sensor of claim 7, wherein the frequency hopping patterncomprises: a periodic, a non-sequential, or a random pattern to switchthe carrier frequency of a plurality of carrier frequencies to anothercarrier frequency of the plurality of carrier frequencies.
 9. Thewireless sensor of claim 7, wherein the processing module is operable toadjust the characteristic by: adjusting capacitance of a tank circuitcoupled to an antenna that receives the series of RF signals, whereinthe wireless sensor includes the tank circuit and the antenna.
 10. Thewireless sensor of claim 7, wherein the processing module is operable toadjust the characteristic by one of: adjusting impedance of an antennaof the wireless sensor to affect the resonant frequency; adjustingcapacitance of a capacitor of the wireless sensor to affect the resonantfrequency, wherein the capacitor includes one or more of a varactor anda selectable capacitor bank; and adjusting inductance of an inductor ofthe wireless sensor to affect the resonant frequency.
 11. The wirelesssensor of claim 7 further comprises: an RF transmitting circuit operableto transmit the set of values to a sensor computing device, wherein thesensor computing device is operable to normalize the set of values toproduce a normalized value that represents a sensed value of theenvironmental condition; or the processing module operable to normalizethe set of values to produce the normalized value and the RFtransmitting circuit operable to send the normalized value to the sensorcomputing device.
 12. The wireless sensor of claim 11, wherein the setof values is normalized by: identifying a subset of the values of theset of values corresponding to a subset of carrier frequencies of aplurality of frequencies of the series of RF signals; and normalizingthe subset of values based on frequency differences between the subsetof carrier frequencies and differences between values of the subset ofvalues.